Dark Energy, Dark Matter - NASA ScienceEventually theorists came up with three sorts of explanations. Maybe it was a result of a long-discarded version of Einstein's theory of gravity, one that contained what was called a "cosmological constant." Maybe there was some strange kind of energy-fluid that filled space. Maybe there is something wrong with Einstein's theory of gravity and a new theory could include some kind of field that creates this cosmic acceleration. Theorists still don't know what the correct explanation is, but they have given the solution a name. It is called dark energy.By pdboyerin Public bookmarkswith accelerationdark_energydark_matterexpandinggravitytheoryuniverse

The Hubble Diagram - Specific InformationTeacher's Guide to Specific Sections Introduction Let students read through the Introduction on their own. Ask them why the discovery that the universe was expanding was so unexpected. Point out that its discovery required three separate threads to come together: Einstein's General Relativity, Slipher's measurements of redshifts, and the building of the new 100" telescope on Mount Wilson. Ask them how the three other lines of evidence support the big bang theory. Get them thinking about how different lines of evidence add up to support a scientific theory. Ask: what makes a good theory?By pdboyerin Public bookmarkswith astronomycosmologyeinsteinsexpandingredshiftsrelativitytelescopeuniverse